586 



KNOWLEDGE & SCIENTIFIC NEWS. 



[NovEMBtiK, igo6. 



The So Called Copper Teeth of 

 Cattle. 



In the Deer Lodge Valley, Montana, adjacent to the 

 great Butte copper district, tlic so-called copper teeth 

 of cattle attract enough attention to make it worthy 

 of record along with the " So-called Gold Coated Teeth 

 of Sheep," as reported in " Knowledcf and Scientific 

 News," \'oI. III., Xo. 15, page 359. 



The lustrous copper or gold coloured coating (popu- 

 larly called "copper teeth,") is general in this region 

 in cattle, and occasionally seen in horses and sheep. 

 The description of the " So-Called Gold Coated Teeth," 

 referred to, accurately described the deposit found on 

 the teeth in the cases here reported. 



.An analysis of this incrustation made by Mr. H. N. 

 Thompson', Chief Chemist of the .Anaconda Copp<^-r 

 Mining Company, shows the deposit to be chiefly 

 c.-ilcium phosphate, with some organic material, but 

 no copper. 



The report of the analysis shows : — 



Insoluble residue, CaO . . 35'5''' 



P...O, . . 34- 5".. 



(CO, 1 



Ignition .c;e . .-Organic ' " ^^ °'" 



( Matter ) 



.An interesting fact in this'connection is that boiling 

 seems to bring out the lustre, and man_ jaws which 

 normally have a blackish or brownish colour, on boiling 

 assume the copper or gold lustre. 



It is worthy of note in this connection that these 

 deposits occur in a region whose waters are strongly 

 alkaline to cochineal solution, and further, because of 

 the arid climate, there are large quantities of .soluble 

 soil constituents present, with a consequent high ash 

 percentage in the plants grown upon it. 



CORRESPONDENCE. 

 Electrical Nitrates and Fertilisers. 



To TiiF. Editors of " Knowledge & Scientific Xews." 



Sirs,— While accepting "J. H. M. H.'s " correction as to 

 the general destination of nitrate of soda as a manure, I 

 should like to point out that the impression of its uses in 

 promoting the growth of wheat is one which is widespread, 

 i'or e.xample, in the opening sentence of Mr. J. B. C. Ker- 

 shaw's article, in the current number of Science Progress, 

 on "The .\rtificial Production of Nitrate of Lime," he 

 begins : — " Since Sir William Crookes startled the scientific 

 world, eight years aijo at Bristol, by pointing out that the 

 corn supply of the world was dependent upon the ample pro- 

 vision of nitrates to the soil, and that we were rapidly de- 

 pleting; our reserves of the only naturally occurring nitrate — 

 namelv, Chili saltpetre — scientists in all countries have been 

 attempting to solve the problem of the e.xtraction of nitrogen 

 Irom the air in the form of nitrite or nitrate." 1 have re- 

 ferred to Sir William Crookes' own observations, and I 

 find that he said : " It is now recognised that all crops re- 

 quire what is called a dominant manure. Some need 

 nitrogen, some potash, others phosphates. Wheat pre- 

 eminently demands nitrosjen, fixed in the form of ammonia 

 or nitric acid," and again, after a long passage referrins; 

 to the cultivation of wheat alone, " The only available com- 

 pound containing sufficient fixed nitrogen to be used on a 

 world-wide scale as a nitrogenous manure is nitrate of 



soda, or Chili saltpetre. This substance occurs native over 

 a narrow band of the plain of Taniarugal in the northern 

 province of Chili. . . The nitrate fields of Chili have 

 become of vast commercial importance, and promise to be 

 of inestimably greater value in the future." 



Sir William Crookes, who, of course, was unaware in 

 1S98 of the experiments (quoted by " J. II. M. H.") taking 

 place in 1905 at Rothamsted, went on to say : " The action 

 of nitrate of soda in improving the yield of wheat has been 

 studied practically by Sir John Lawes and Sir Henry (lilbert 

 on their experimental field at Rothamsted. This field was 

 sown with wheat for thirteen consecutive years without 

 manure, and yielded an average of 11.9 bushels to the acre. 

 For the next thirteen years it was sown with wheat, and 

 dressed with 5 cwt. of nitrate of soda per acre, other mineral 

 constituents being present. The average yield for these 

 vears was 36.4 bushels per acre, an increase of 24.5 bushels. 

 In other words, 22. 86 lbs. of nitrate of soda produce an in- 

 crease of one bushel of wheat." 



I trust that "J. H. M. H." will take steps to make Sir 



William Crookes aware of the extraordinary error into 



which ho fell in believing that " wheat was in any sense 



dependent for its profitable cultivation upon nitrate of soda." 



I am, sir. 



Yours faithfully, 

 G. 



Sunspots and Cold. 



To THE Editors of " Knowledge & Scientific News." 

 .Sirs, — In an article on " Coming Cold " in " Know- 

 ledge " for 1897, p. 241, is a diagram which seemed to me 

 sue'grestive of a connection between sunspots and winter cold 

 in the early part of the year (as measured by the number of 

 frost days at Greenwich). 



It mii,dit interest some of your readers to see how things 

 have turned out in those nine years from 1897. 



The thin curve .\ shows, then, the variations in number 

 of frost days in the earlier half of each year, and in the 

 thick curve each year point represents an average of five 

 values. Below (B) is the inverted sunspot cur\e. 



In that article I wrote : " It seems to the present writer 

 that we are now about the beginninp: of another of those 

 long waves of the smoothed curve of frost days, which may 

 be expected to culminate near the next sunspot minimum. 



